IT202100018032A1 - GAS TURBINE - Google Patents

Description

DESCRIPTION

of the patent for industrial invention entitled:

?GAS TURBINE?

FIELD

This subject matter relates generally to gas turbine engines including gear sets.

BACKGROUND

A ducted turbofan engine operates on the principle that a turbomachine drives a fan assembly, the fan assembly being located at a radial location from an engine nacelle and the turbomachine. With an open rotor turbofan engine, otherwise, the fan assembly is not? bordered by a gondola and therefore pu? include a fan assembly having a larger diameter. A gear transmission can? be provided at an axial location between the impeller and a power turbine of the turbomachinery.

In any case, the turbomachine pu? include a compressor section, a combustion section and a turbine section in serial flow order. Traditionally, the turbine section includes a turbine having a turbine having a plurality of of turbine rotor blade stages coupled together to extract energy from the flue gases from the combustion section. Between the turbine rotor blade stages are positioned stator vane stages to straighten the flue gas flow and to increase an efficiency of the turbine.

Counter-rotating turbines have been proposed whereby alternating stages of counter-rotating turbine rotor blades are provided, obviating the need for counter-rotating turbines. of at least some of the turbine rotor blade stages, potentially reducing the length and weight of the turbine section. However, challenges can arise as to how to utilize the counter-rotating outputs from such a turbine. Accordingly, a means to effectively utilize the counter-rotating outputs from such a turbine would be useful.

SHORT DESCRIPTION

Aspects and advantages of the present disclosure will be set forth in part in the following description or may be obvious from the description or can be learned through practice of the present disclosure.

In an exemplary embodiment of the present disclosure, ? provided a gas turbine engine. The gas turbine engine includes a fan assembly having a plurality of of fan blades; and a turbomachine. The turbomachinery includes a compressor section, a combustion section and a turbine section in serial flow order. The turbomachine further includes a first input power source; a second input power source configured to counter-rotate with respect to the first input power source; a power output component operatively connected to the fan assembly; and a gear set located in front of the combustion section of the turbomachine, the gear set configured to receive power from the first input power source and the second input power source and to supply power to the power output component, the set of gears including a helical gear.

These and other features, these and other aspects and advantages of the present disclosure will be better understood by referring to the following description and the appended claims. The accompanying drawings, which are incorporated into and form a part of this specification, illustrate embodiments of the disclosure and, together with the description, serve to explain principles of the disclosure.

BRIEF DESCRIPTION OF THE DRAWINGS

A full and complete disclosure of this disclosure, including how it is better, addressed to a common expert in the technique, ? reported in the specification, which refers to the attached figures, where:

figure 1A ? a side, schematic view of a gas turbine engine according to an exemplary embodiment of the present disclosure.

Figure 1B ? a side, schematic view of a gas turbine engine according to another exemplary embodiment of the present disclosure.

Figure 2 ? a side, schematic view of a gas turbine engine according to yet another exemplary embodiment of the present disclosure.

Figure 3 ? a side, schematic view of a gas turbine engine according to yet another exemplary embodiment of the present disclosure.

Figure 4 ? a close-up view of a turbomachine having a gear train according to an exemplary embodiment of the present disclosure.

Figure 5 ? a close-up view of a first portion of the exemplary gear set of Figure 4.

Figure 6 ? a close-up view of a second portion of the exemplary gear set of Figure 4.

Figure 7 ? a perspective view of a pair of single helical gears according to an exemplary embodiment of the present disclosure.

Figure 8 ? a plan view of a first of the pair of single helical gears of figure 7.

Figure 9 ? a close-up view of a turbomachine having a gear train according to another exemplary embodiment of the present disclosure.

Figure 10 ? a close-up view of a turbomachine having a gear train according to another exemplary embodiment of the present disclosure.

Figure 11 ? a perspective view of a pair of spur gears according to an exemplary embodiment of the present disclosure.

Figure 12 ? a plan view of a first of the pair of spur gears of figure 11.

DETAILED DESCRIPTION

Will it be done? I now refer in detail to the present disclosure embodiments, one or more? examples of which are illustrated in the accompanying drawings. The detailed description uses numeric and alphabetic designations to refer to features in the drawings. The same or similar designations in the drawings and the specification have been used to refer to the same or similar portions of the disclosure.

The term "exemplary"? used herein to mean "serving as an example, case or illustration". Any implementation described herein as "exemplary" is not necessarily to be considered as preferred or advantageous over other implementations. In addition, unless specifically identified otherwise, all embodiments described herein should be considered exemplary.

As used herein, the terms "first", "second" and "third" may be used interchangeably to distinguish one component from another and are not intended to indicate the location or importance of any individual component.

The terms "front" and "rear" refer to relative positions within a gas turbine engine or vehicle and refer to the normal operating state of the gas turbine engine or vehicle. For example, with respect to a gas turbine engine, front refers to a lower position. close to an entrance to the engine and rear refers to a position pi? near a nozzle or engine exhaust.

The terms "upstream" and "downstream" refer to the direction relative to fluid flow in a fluid path. For example, "upstream" refers to the direction from which the fluid flows and "downstream" refers to the direction in which the fluid flows.

The terms "mated", "attached", "attached to" and the like refer to both direct coupling, attachment or attachment as well as indirect coupling, attachment or attachment through one or more elements. intermediate components or features, unless otherwise specified herein.

The singular forms "un/uno/una" and "il/lo/la" include references to the plural unless the context clearly indicates otherwise.

The language of approximation, as used herein throughout the specification and claims, is applied to modify any quantitative representation that could possibly vary without causing a change of the basis function to which ? related. Consequently, a value modified by a term or terms, such as "approximately", "approximately", and "substantially" need not be limited to the precise value specified. In at least some cases, the approximation language can correspond to the precision of an instrument for measuring value or the precision of the methods or machines for making or producing the components and/or systems. For example, the approximation language can? refer to as within a margin of 1, 2, 4, 10, 15 or 20 percent. These margins of approximation can apply to a single value, one or both endpoints by defining numerical ranges and/or the margin for the intervals between the endpoints.

Herein and throughout the specification and claims, range limitations are combined and interchanged with each other, such ranges are identified and include all sub-ranges contained within them unless the context or language dictates otherwise. For example, all ranges described herein include endpoints and the endpoints are independently combinable with each other.

The expression "in the vicinity?" indicates more closer to one object than to another. For example, the sentence "A is in close proximity to X with respect to Y" indicates that the object A is more close to object X than it is? to object Y.

The term "turbomachine" or "turbomachinery" refers to a machine including one or more compressors, a section of combustion and one or more? turbines which together generate a torque output.

The term "gas turbine engine" refers to an engine having turbomachinery over all or a portion of its power source. Exemplary gas turbine engines include turbofan engines, turboprop engines, turbojet engines, turboshaft engines, etc. Unless otherwise specified or made clear by the context, the term gas turbine engine is not limited to aeronautical gas turbine engines and pu? include industrial gas turbine engines, aeronautical gas turbine engines, etc.

The term "combustion section" refers to any heat adding system for a turbomachinery. For example, the expression combustion section can? refer to a section including one or more? between a blasting combustion unit, a rotary detonating combustion unit, a pulsed detonating combustion unit or other suitable heat adding unit. In some exemplary embodiments, the combustion section may include an annular combustor, chamber combustor, cannular combustor, trapped vortex combustor (TVC), or other appropriate combustion system, or combinations thereof.

The terms "low" and "high", or their respective comparative degrees (e.g. low/high, where applicable), when used with a compressor, turbine, shaft or spool components, etc. each refer to the speeds? related within an engine unless specified otherwise. For example, a "low turbine" or "low speed turbine" is refers to a component configured to operate at a speed? of rotation, which is a speed? of maximum allowed rotation, lower than a "high turbine" or "high speed turbine?" of the engine.

The term "helical gear" refers to a type of spur gear having an obliquely inclined tooth track in one or more gears. directions. Helical gear can? refer to a single helical gear, a double helical gear, etc.

The term "single helical gear" refers to a type of spur gear with an oblique tooth track inclined in one direction, as defined and further described below with reference to FIGS. 7 and 8. Single helical gears generally allow a large ratio of contact and provide low vibration while being able to transmit a large force in a direction parallel to their center lines.

The term "spur gear" refers to a type of spur gear in which one edge of each tooth is straight and aligned parallel to a gear centerline or rather a gear rotational axis, as further defined and described below with reference to Figures 11 and 12. Spur gears generally allow torque transmission within of the force transmission in a direction parallel to their center lines.

The expression "thrust bearing" refers to a bearing that ? Capable of supporting an axial load between a first component and a second component. In some embodiments, the thrust bearing may be a ball bearing, tapered roller bearing, fluid bearing, spherical roller bearing or the like.

The term "non-thrust bearing" refers to a bearing that is not ? capable of supporting a substantial axial load (for example, unable to withstand an axial load greater than 10% or 5% of the bearing's radial load capacity). In some embodiments, the non-thrust bearing may be a roller bearing, a fluid bearing or the like.

Thrust bearings and non-thrust bearings according to the present invention can be formed from a metallic material, a metal alloy, a ceramic or any other suitable material. In alternate embodiments, the thrust bearing and/or non-thrust bearing may be a fluid bearing.

The term "gear ratio" without a modifying element refers to a maximum gear ratio for a gear set.

The term "maximum gear ratio" refers to a gear ratio for a gear set measured as the ratio of an input plus? fast speed? (in g/min (RPM)) and a speed? of output rotation (also in rpm).

The term "minimum gear ratio" refers to a gear ratio for a gear set measured as the ratio of an input plus? slow speed? of rotation (in g/min) and a speed? of output rotation (also in rpm).

In some exemplary aspects of this disclosure, ? provided a gas turbine engine having a fan assembly and a turbomachinery. The turbomachinery generally includes a compressor section, a combustion section and a turbine section in serial flow order. The turbomachine further includes a first input power source, a second input power source configured to counter-rotate relative to the first input power source, and a power output component operatively connected to the fan assembly for driving a plurality of input power sources. of fan blades of the fan assembly.

For example, the turbine section of the turbomachine can? include a counter-rotating turbine having a first plurality? of turbine rotor blades configured to rotate in a first direction and a second plurality of turbine rotor blades configured to rotate in a second direction opposite to the first direction. The first plurality? of turbine rotor blades can? be interdigitated with the second plurality? of turbine rotor blades (for example, spaced alternately). The first input power source can? be revolving with the first plurality? of turbine rotor blades and the second source of input power can? be revolving with the second plurality? of turbine rotor blades.

The exemplary gas turbine engine highlighted above further includes a gear train located forward of the combustion section of the turbomachine configured to receive power from the first input power source and the second input power source and further configured to supply power to the component of power output. In this way, the group of gears can? facilitating the driving of the power output component and the fan assembly with the rotational power provided by the first input power source and the second input power source.

Pi? specifically, for at least one embodiment, the gear set includes at least one helical gear, such as a single helical gear. For example, the group of gears can? defining a first torque path extending from the first input power source to the power output component and a second torque path extending from the second input power source to the torque output component. The group of gears can? including the at least one single helical gear within the first torque path or within the second torque path. For example, in at least some embodiments, the gear set can include single helical gears all along the first torque path, all along the second torque path, or both such that the only gears used to transfer torque in the first torque path, second torque path, or both are single gears twisted.

With such an exemplary embodiment, the engine can? be configured to provide all or a portion of an axle load to which ? subjects the fan assembly during engine operation from the power output component to the first input power source, the second input power source, or both. The use of single helical gears can? provide this functionality? in an axially compact whole. As will be appreciated, the first input power source, the second input power source, or both may be rotatable with a turbine of the turbine section. During operation of the gas turbine engine, the turbine(s) may be subjected to an axial load in a direction opposite to an axial load direction at which it is subjected the fan assembly. Consequently, providing the transfer of an axial load from the power output component to the first input power source, the second input power source, or both, can? a net axial load which must be absorbed by a thrust bearing can be reduced.

Further, in the above exemplary embodiment, or in an alternate exemplary embodiment, the gas turbine engine may include an inter-shaft bearing positioned between the first input power source and the power output component. This can provide a desired stabilization.

Furthermore, such a configuration provides the opportunity to provide an additional or alternative path to transfer an axle load to which ? subjecting the fan assembly to the first input power source, the second input power source, or both. To facilitate this transfer, a net axial load must be absorbed by a thrust bearing during engine operation. Pi? specifically, in some embodiments, the inter-shaft bearing can? be configured as a thrust bearing. In such an exemplary aspect, all or a portion of an axial load on the fan assembly during engine operation can occur. be transferred from the power output component, through the inter-shaft bearing (configured as a thrust bearing), and to the first input power source. The inter-shaft bearing can? thereby allowing axial loads acting on a turbine of the turbine section to at least partially deflect axial loads acting on the fan assembly during engine operation. Consequently, by providing for the transfer of an axial load from the power output component to the first input power source, a net axial load which must be absorbed by a thrust bearing can? be reduced. With such a configuration, the engine pu? Also include a thrust bearing, for example, on the power output component to ground the assembly.

Further, again, in one or both of the above exemplary embodiments, or in an alternate exemplary embodiment, the gas turbine engine may further include a first thrust bearing located forward of the combustion section of the turbomachine and supporting the first input power source, and also a second thrust bearing located forward of the combustion section of the turbomachine and supporting the second input power source entrance. Such a configuration can? provide unique benefits for a turbomachinery including a counter-rotating turbine. For example, by locating both the first and second thrust bearing in front of the combustion section, for example near? of the gear set with respect to the combustion section, any thermal expansion to which ? subjected the first input power source between the first thrust bearing and a first plurality? of turbine rotor blades of the counter-rotating turbine to which ? coupled to the first source of input power will have? a minimal effect on the axial games between the first plurality? of turbine rotor blades and a second plurality? of turbine rotor blades of the counter-rotating turbine to which ? coupled the second input power source, given that the second input power source will be? subjected to similar thermal expansion.

Referring now to the drawings, FIG. 1A is an exemplary embodiment of an engine 10 in accordance with aspects of the present disclosure. The motor 10 defines an axial direction A and an axial centerline 12 extending along the axial direction A, a radial direction R with respect to the axial centerline 12 and a circumferential direction C extending around the axial centerline 12.

The engine 10 includes a fan assembly 14 and a turbomachine 16. In various embodiments, the turbomachine 16 is a Brayton cycle system configured to drive fan assembly 14. Turbomachinery 16 ? shielded, at least in part, by an outer casing 18. The fan assembly 14 includes a plurality of of fan blades 13. A group of fins 20 ? provided extending from the outer shell 18. The fin assembly 20 includes a plurality of of vanes 15 positioned in operative arrangement with the impeller blades 13 to provide thrust, control the thrust vector, suppress or redirect unwanted acoustic noise, or otherwise desirably alter a flow of air relative to the impeller blades 13. In some forms of embodiment, the impeller assembly 14 includes between three (3) and twenty (20) impeller blades 13. In some embodiments, the vane assembly 20 includes an amount equal or smaller than the fins 15 with respect to the fan blades 13 or a quantity? larger than the fins 15 than the fan blades 13.

In some embodiments, as shown in FIG. 1A, the fin assembly 20 is positioned downstream or behind the fan assembly 14. However, it should be appreciated that in some embodiments the fin assembly 20 may be positioned upstream or in front of the fan assembly 14. In still various embodiments, the motor 10 can? include a first set of fins positioned in front of the fan assembly 14 and a second set of fins positioned behind the fan assembly 14. The fan assembly 14 can? be configured to desirably adjust the pitch at one or more? impeller blades 13, for example to control thrust vector, dampen or redirect noise, or alter thrust output. The group of fins 20 pu? be configured to desirably adjust the pitch at one or more? fins 15, for example to control the thrust vector, abate or redirect noise, or alter the thrust output. The pitch control mechanisms at either or both of the fan assembly 14 or the vane assembly 20 may cooperate to produce one or more desired effects described above.

In some embodiments, as shown in FIG. 1A, the motor 10 is a system of production thrust not intubated, in such a way that the plurality? of fan blades 13 is unshielded by a fan nacelle or casing. As such, in various embodiments, the engine 10 can be referred to as an unshielded turbofan engine or an open rotor engine. In particular embodiments, the engine 10 ? a single non-ducted rotor motor including a single row of non-ducted fan poles 13.

It will be appreciated, however, that in other exemplary embodiments aspects of the present disclosure may be applied in addition or as an alternative to a motor 10 having any other suitable configuration. For example, referring briefly to FIG. 1B, ? represented an engine according to another embodiment. The exemplary engine 10 of FIG. 1B ? configured in substantially the same manner as in FIG. 1A, however, for the FIG. 1B embodiment, the engine further includes an outer nacelle, or conduit, 19. The outer nacelle 19 is configured in substantially the same manner as in FIG. supported by fin group 20.

Referring now to FIG. 2, ? provided is a schematic view of an exemplary embodiment of a motor 10 according to the present disclosure. As with the embodiment of Fig. 1A , the engine 10 of Fig. 2 includes a fan assembly 14 and a turbomachine 16 and defines an axial direction A, an axial centerline 12 extending along the axial direction A, a radial direction R with respect to the axial centerline 12, a first circumferential direction C1 and a second circumferential direction C2. Turbomachinery 16 includes a compressor section 21, a combustion section 26 and a turbine section 33 together in serial flow arrangement. Turbomachine 16 also includes a high speed spool. which includes a high-speed compressor? 24 and a high-speed turbine? 28 operatively coupled in rotation together by a high speed shaft? 27. The combustion section 26 ? positioned between the high-speed compressor? 24 and the high-speed turbine? 28.

Referring again to FIG. 2, the turbomachine 16 further includes a booster or low speed compressor. 22 within the compressor section 21 coupled to a first turbine 30 within the turbine section 33 via a first shaft 29. 22 ? positioned in flow relationship with the high-speed compressor? 24 at a location upstream of the high speed compressor? 24. The first turbine 30 ? positioned in flow relationship with the high-speed turbine? 28 at a location downstream of the high speed turbine? 28.

Various embodiments of the turbine section 33 further include a second turbine 32 within the turbine section 33, rotatably coupled to a second shaft 31. The second turbine 32 is rotatably coupled to a second shaft 31. positioned in flow relationship with the first turbine 30 at a location downstream of the first turbine 30.

The engine 10 further includes a gear set 100 located forward of the combustion section 26 of the turbomachine 16. The first turbine 30 and the second turbine 32 are each operatively connected to the gear set 100 to supply power to a power output component and to the impeller assembly 14. In at least some exemplary embodiments, the first turbine 30 can? be configured to rotate in the first circumferential direction C1 and the second turbine 32 can? be configured to rotate in a second circumferential direction C2.

Pi? specifically, the group of gears 100 ? configured to transfer power from the turbine section 33 and to reduce a speed? of output rotation at the impeller assembly 14 relative to one or both turbines 30, 32. Embodiments of the gear assembly 100, as shown and described below, may allow suitable gear ratios for, for example, large diameter non-ducted fans (see, for example, Figure 1A) and high-speed turbines relatively tall and/or relatively small in diameter (see, for example, Fig. 1B ), such as turbines 30, 32. In addition, the embodiments of the gear set 100 provided herein may be suitable within radial constraints or diameters of the turbomachine 16 within the outer casing 18 at the location forward of the combustion section 26.

Will you appreciate it? that for a gearset having two inputs and one output, two gear ratios may be required to fully describe the meshing of the gearset 100. In particular, the gearset 100 defines a maximum gear ratio and a gear ratio minimum transmission. The maximum transmission ratio pu? be measured as the ratio between an input pi? fast speed? of rotation (in g/min) and a speed? of output rotation (also in rpm). The minimum transmission ratio pu? be measured as the ratio between an input pi? slow speed? of rotation (in g/min) and a speed? of output rotation (also in rpm). The gear ratio without a modifying element refers to the maximum gear ratio.

Embodiments of the gear set 100 shown and described herein can allow for maximum gear ratios up to 14:1. Still other various embodiments of the gear set 100 provided herein may allow for maximum gear ratios of at least 3:1. Still other various embodiments of the gearset 100 provided herein allow for maximum gear ratios between 4:1 and 12:1 for a two-stage epicyclic gearset or composite gearset, such as those described below. The minimum transmission ratio pu? be less than the maximum gear ratio, for example greater than approximately 1:1. For example, the minimum gear ratio pu? be 5% less than the maximum gear ratio, for example 10% less, 20% less, 30% less, 40% less, 50% less, 60% less, 70% less, 80% less than the maximum gear ratio. The minimum transmission ratio pu? be at least 7% of the maximum gear ratio, e.g. at least 10% of the maximum gear ratio, e.g. at least 15% of the maximum gear ratio, e.g. at least 25% of the maximum gear ratio, e.g. at least 35% of the maximum gear ratio, for example at least 50% of the maximum gear ratio.

It should be appreciated that the embodiments of the gear set 100 provided herein may allow for large gear ratios as provided herein between the turbine section 33 and the fan assembly 14 or particularly between a first turbine 30 and the fan 14, between a second turbine 32 and the fan assembly 14 or both.

The engine of the figure 2 pu? be an unshielded or open rotor motor, like the one in figure 1A, or can? be a ducted motor, like the one in Figure 1B. In addition, it should be appreciated that aspects of the disclosure provided herein may be applied to partially ducted engines, rear fan engines, or other gas turbine engine configurations, including those for marine, industrial, or aeropropulsion systems. Some aspects of the disclosure may be applicable to, for example, turbofan, turboprop, or turboshaft engines. However, it should be appreciated that some aspects of the disclosure may address issues that may be particular to unshielded or open rotor motors, such as, but not limited to, issues related to gear ratios, impeller diameter, speed, and speed. fan or combinations thereof.

Also, will you appreciate it? that in other exemplary embodiments, the turbomachine 16 can? have any other suitable configuration. For example, referring now to FIG. 3, ? provided is a schematic view of an exemplary embodiment of a motor 10 according to another embodiment of the present disclosure. The exemplary engine 10 of FIG. 3 ? configured in substantially the same manner as the exemplary turbomachine 16 of Figure 2.

However, for the embodiment of Fig. 3 , a turbomachine 16 of engine 10 includes one or more interdigitated structures at the compressor section 21, at the turbine section 33, or both. Particularly for the embodiment shown, a turbine section 33 includes a second turbine 32 interdigitated with a first turbine 30, for example through a rotating outer shield, drum, casing or rotor. While not shown, it should be appreciated that embodiments of turbine section 33 may additionally include first and/or second turbines 30, 32 interdigitated with one or more stages of the high-speed turbine? 28.

Pi? Specifically, for the exemplary embodiment shown, you will appreciate that the first turbine 30 includes a first plurality? of turbine rotor blades 44 and the second turbine 32 includes a second plurality of turbine rotor blades 46. The first turbine 30 and the first plurality? of turbine rotor blades 44 are configured to rotate in a first and lower direction. specifically, in a first circumferential direction C1 with respect to the axial center line 12. The second turbine 32 and the second plurality? of turbine rotor blades 46 are configured to rotate in a second and more? specifically, in a second circumferential direction C2 with respect to the axial centerline 12. The second circumferential direction ? opposite to the first circumferential direction. Thus, the first turbine 30 and the second turbine 32 can be configured together as a counter-rotating turbine. Such a configuration can? obviate the need of one or more stationary guide vane stages between adjacent turbine rotor blade stages, potentially resulting in a faster engine. light and axially more? compact 10.

In another embodiment, the compressor section 21 includes the low speed compressor. 22 interdigitated with the high-speed compressor? 24.

Referring again to figure 3, you will appreciate that the engine 10 includes a first turbine section bearing 40 which supports the first turbine 30 and shaft 29 at a location behind the combustion section 26 and a second turbine section bearing 42 which supports the second turbine 32 and shaft 31 also at a location behind the combustion section 26. How will it come? explained in greater detail below, depending on how these shafts 29, 31 are supported within or in front of the compressor section 21, the turbine section bearings 40, 42 may be thrust bearings or alternatively may be roller or other non-thrust bearing.

Referring now to FIG. 4, ? provided is a close-up, cross-sectional view of a gas turbine engine 10 according to another exemplary embodiment of the present disclosure. The exemplary gas turbine engine 10 of FIG. 4 can be configured in a similar way to one or more? of the exemplary gas turbine engines 10 described above with reference to FIGS. 1 through 3 . that the exemplary gas turbine engine 10 of FIG. 4 generally includes a fan assembly 14 having a plurality of of fan blades 13, a turbomachine 16, a combustion section 26 (not shown; see FIGS. 2 and 3) and a turbine section 33 (not shown; see FIGS. 2 and 3) in serial flow order .

Further, the exemplary turbomachine 16 depicted in Figure 4 additionally includes a first input power source 102 and a second input power source 104 configured to counter-rotate relative to the first input power source 102. The first power source input 102 can? be rotatable with either the first turbine 30 or second turbine 32 in FIGS. 2 and 3 and the second input power source 104 may be rotatable. be rotatable with the other between the first turbine 30 or the second turbine 32 in Figures 2 and 3. More? specifically, for the exemplary embodiment of Figure 4 , the first input power source 102 is a low-speed input power source? (for example, corresponding to turbine 32 and shaft 31 in FIGS. 2 and 3) and second input power source 104 ? a high-speed input power source? (corresponding to turbine 30 and shaft 29 in figures 2 and 3).

Furthermore, the exemplary turbomachine 16 of FIG. 4 additionally includes a power output component 106 operatively connected to the fan assembly 14. More? specifically, how will it come? described in greater detail below, the power output component 106 includes a rotatable fan shaft 108 with fan blades 13 for driving the plurality of fan blades. of fan blades 13.

Further, again, the exemplary turbomachine 16 of FIG. 4 additionally includes a gear set 100 located forward of the combustion section 26 of the turbomachine 16. specifically, in the exemplary embodiment shown, the gear set 100 is located in front of the compressor at low speed? 22 of the compressor section 21 of the turbomachine 16. The gear set 100 ? configured to receive power from the first input power source 102 and the second input power source 104 and to supply power to the power output component 106. that the group of gears 100 ? configured to receive power from two separate power sources and to supply power to a single output (the power output component 106).

In the embodiment shown, the gear set 100 generally includes a first epicyclic gear 110 configured to operatively connect the first input power source 102 to the power output component 106 and a second epicyclic gear 112 configured to operatively connect the second source of input power 104 to the power output component 106.

Will you appreciate it? that although a single first epicyclic gear 110 and a single second epicyclic gear 112 are shown in the cross-sectional view of FIG. include a plurality? of first epicycloidal gears 110 and a plurality? of second epicyclic gears 112. For example, the group of gears 100 pu? include between two and six first epicyclic gears 110 and between two and six second epicyclic gears 112.

The first epicyclic gear 110 and the second epicyclic gear 112 are rotatably mounted on a planetary carrier 114. For example, the first epicyclic gear 110 defines a first epicyclic gear axis 116 and the second epicyclic gear 112 defines a second epicyclic gear epicyclic 118. The first epicyclic gear 110 ? configured to rotate circumferentially about the first epicyclic gear axis 116 and the second epicyclic gear 112 ? configured to rotate circumferentially about the second axis of epicyclic gearing 118.

As will be appreciated, the turbomachine 16 further includes a structural, stationary member 120 and the planetary gear carrier 114 ? mounted on the structural element 120. Pi? Specifically, the turbomachine 16 includes an epicyclic gear mounting member 122 that extends from the planetary carrier 114 to the structural member 120. extend between the adjacent first and second epicyclic gears 110, 112 in the circumferential direction C (see Figs. 5 and 6 , discussed below).

Referring also briefly to Fig. 5 , which provides a close-up view of the first epicyclic gear 110 of the gear set 100, it will be appreciated that the first epicyclic gear 110 generally includes a first front gear 124 and a first rear gear 126. Furthermore, the first input power source 102 includes a first sun gear 128 and the power output component 106 comprises an output sun gear 130. The first sun gear 128 of the first input power source 102 is configured to mesh with the first rear gear 126 of the first epicyclic gear 110 and the first front gear 124 of the first epicyclic gear 110 ? configured to mesh with the output sun gear 130 of the power output component 106. In all figures, the meshing of the two gears is usually indicated by a transparent line. Thus, the gear set 100 defines a first torque path from the first input power source 102, through the first epicyclic gear 110 and to the power output component 106.

Referring again to Fig. 4 and also briefly to Fig. 6 , which provides a close-up view of the second epicyclic gear 112 of the gear set 100, it will be appreciated that the second epicyclic gear 112 generally includes a second front gear 132 and a second rear gear 134. Furthermore, the second input power source 104 includes a second sun gear 136 and the power output component 106 comprises a ring gear 138 The second sun gear 136 of the second input power source 104? configured to mesh with the second rear gear 134 of the second epicyclic gear 112 and the second front gear 132 of the second epicyclic gear 112 ? configured to mesh with the ring gear 138 of the power output component 106. Thus, the gear set 100 additionally defines a second torque path from the second input power source 104, through the second epicyclic gear 112 and towards the power output component 106.

Aspect to highlight, the first 110 epicyclic gear? configured to rotate at a different speed? of rotation with respect to the second input power source 104 or more? specifically, at a different speed? of rotation with respect to the second sun gear 136 and also at a different speed? of rotation with respect to the ring gear 138 of the power output component 106 (see, for example, Fig. 5 ). Similarly, the second epicyclic gear 112 ? configured to rotate at a different speed? of rotation with respect to the first input power source 102 or more? specifically, at a different speed? of rotation with respect to the first sun gear 128 and also at a different speed? of rotation with respect to the output sun gear 130 of the power output component 106 (see, for example, Fig. 6 ).

Referring again to Figure 4, you will appreciate that the exemplary turbomachinery 16 shown in FIG. 4? configured to transfer an axial load from the fan assembly 14 to the first input power source 102, the second input power source 104, or both during engine operation. For example, will you appreciate it? that the fan group 14 can? be subjected to a relatively large axial load during operation as a result of a quantity? thrust generated by a rotation of the plurality? of fan blades 13 of the fan assembly 14. Further, when the first input power source 102 and the second input power source 104 are each coupled to a turbine of the turbine section 33 of the turbomachinery 16, the first input power 102 and the second input power source 104 can be subjected to an axial load in an opposite direction along the axial direction A, the axial load at which ? subjected to the impeller assembly 14 during operation of the gas turbine engine 10. As a result, by transferring all or a portion of the axial load on the impeller assembly 14 to the first input power source 102, to the second input power source 104 or both, a net axial load pi? small pu? having to be borne by one or more? thrust bearings, as described below.

In particular, for the exemplary embodiment of Figures 4 to 6 , the gear set 100 includes at least one helical gear. For example, the first 110 epicyclic gear can? include the at least one helical gear. Pi? specifically, for the embodiment shown, the output sun gear 130 of the power output component 106, the first front gear 124 of the first epicyclic gear 110, the first rear gear 126 of the first epicyclic gear 110 and the first gear solar gear 128 of the first input power source 102 are each configured as a helical gear.

Pi? specifically, the gear set 100 includes at least a single helical gear. For example, the first 110 epicyclic gear can? include at least a single helical gear. Pi? specifically, for the embodiment shown, the output sun gear 130 of the power output component 106, the first front gear 124 of the first epicyclic gear 110, the first rear gear 126 of the first epicyclic gear 110 and the first gear solar gear 128 of the first input power source 102 are each configured as a single helical gear.

In this way, the gear group 100 can? further defining a first coaxial channel path from the power output component 106, through the first epicyclic gear 110, to the first input power source 102, similar to the first torque path.

Will you appreciate it? that as used herein, the term "helical gear" refers to a type of spur gear having an obliquely inclined tooth track in one or more directions. The term "single helical gear" refers to a type of spur gear with an oblique tooth track inclined in one direction. For example, referring briefly to FIG. 7, by reference ? A pair of exemplary single helical gears is shown. Pi? Specifically, Figure 7 shows a first single helical gear 202 and a second single helical gear 204 configured to mesh with the first single helical gear 202. The first single helical gear 202 includes a first plurality of of teeth 206 circumferentially spaced and oriented in a first direction 208 with respect to a first center line 210 of the first single helical gear 202. The second single helical gear 204 includes a second plurality of of teeth 212 circumferentially spaced apart and oriented in a second direction 214 with respect to a second center line 216 of the second single helical gear 204. The first direction 208 is opposite to the second direction 214.

Also, referring briefly now to FIG. 8 , which provides a plan view of one side of the first single helical gear 202 and the first plurality of of teeth 206, will you appreciate? that the first direction 208 of the first plurality? of teeth 206 defines a helix angle 218 with the first center line 210. Aspect to highlight, the first plurality? of teeth 206 each define a relatively straight shape. In other embodiments, however, the first plurality? of teeth 206 pu? define a single curved shape, multiple curved shape, etc. Nonetheless, the first direction 208 pu? refer to an imaginary line extending from a start on the left side of a tooth at an outer leading edge to an extreme? on the right side of the same tooth at the outer leading edge. The second single helical gear 204 can? define the same helix angle, but opposite.

The helix angle 218 can? be between about 10 degrees and about 60 degrees, for example between about 15 degrees and about 45 degrees.

Single helical gears generally allow for a larger contact ratio and provide reduced vibration while being able to transmit a large force in a direction parallel to their centerlines.

Referring again now to figures 4 to 6, it will be appreciated that for the embodiment shown, the second epicyclic gear 112 further includes at least one helical gear. In particular, for the embodiment of Figs. 4 to 6 , the ring gear 138 of the power output component 106, the second front gear 132 of the second epicyclic gear 112, the second rear gear 134 of the second epicyclic gear 112 and the second sun gear 136 of the second input power source 104 are each also configured as a helical gear.

Pi? specifically, you will appreciate? that for the embodiment shown, the second epicyclic gear 112 further includes at least a single helical gear. In particular, the ring gear 138 of the power output component 106, the second front gear 132 of the second epicyclic gear 112, the second rear gear 134 of the second epicyclic gear 112 and the second sun gear 136 and of the second power source input gear 104 are also each configured as a single helical gear.

In this way, the gear group 100 can? further defining a second axial load path from the power output component 106, through the second epicyclic gear 112 to the second input power source 104, similar to the second torque path.

Of note, the power output component 106 further includes a shaft extension 140 which extends between the fan shaft 108 and the ring gear 138. desired amount of load transfer of an axial load from the power output component 106 to the ring gear 138, the shaft extension 140 defines an extension angle 142 with the axial centerline 12 greater than or equal to approximately 15 degrees and less than equal to approximately 90 degrees, such as greater than or equal to approximately 25 degrees and less than or equal to approximately 75 degrees. In some embodiments, the extension angle 142 can be greater than or equal to approximately 30 degrees, such as greater than or equal to approximately 45 degrees and less than or equal to approximately 60 degrees. The extension angle 142 can? be defined between a reference line 144 extending along the major part of the shaft extension 140 in a plane defined by the radial direction R and the axial direction A (the plane shown in Fig. 4 ), extending through the center line axial 12.

Also, for the exemplary gas turbine engine 10 shown in Figure 4 , the gas turbine engine 10 allows for an additional axial load path parallel to the first axial load path. Pi? specifically, the gas turbine engine 10 further includes an inter-shaft bearing 146 positioned between the first input power source 102 and the power output component 106. In the embodiment shown, the inter-shaft bearing 146 is configured as a thrust bearing. In this way, it will be appreciated that the gas turbine engine 10 defines a third axial load path from the power output component 106, through the inter-shaft bearing 146, to the first input power source 102.

Will you appreciate it? that the third axial load path ? arranged parallel to the first axial load path. Consequently, during operation of the gas turbine engine 10, a first portion of an axial load on the impeller assembly 14 and power output component 106 may occur. be configured to go through the gear set 100 by means of the helical gear and more? specifically by means of the first epicyclic gear 110, towards the first input power source 102 (along the first axial load path) and a second portion of the axial load on the power output component 106 can? be configured to pass through the inter-shaft bearing 146 to the first input power source 102 (along the third axial load path).

Briefly, it will appreciate? furthermore, that a third portion of the axial load on the power output component 106 can be configured for transfer to a structural member 120 via a first bearing 148 (each described below). This portion of the axial load transferred to the structural element 120 can be a thrust load for the gas turbine engine 10.

For the embodiment shown, with the parallel axial load paths between the power output component 106 and the first input power source 102, an axial load to be transferred through the inter-shaft bearing 146 can be low enough to accommodate a relatively small thrust bearing, such as the one shown. Most notably, the power output component 106 and the first input power source 102 can be configured to co-rotate (i.e., rotate in the same circumferential direction as each other). Also, with such a configuration, you will appreciate the that the inter-shaft bearing 146 can? be located inwardly along the radial direction R of at least one gear of gear set 100. can? facilitate both radially and axially compact gear set 100 for the gas turbine engine 10.

Aspect to highlight, the inter-shaft bearing 146? the primary thrust bearing for the first input power source 102. Thus, the inter-shaft bearing 146 can? support all or substantially all thrust loads on the first input power source 102. However, a separate bearing (a non-thrust bearing) can? be provided at a location not shown (e.g., behind the combustion section 26) separately providing radial support for the first input power source 102.

How will you appreciate it? Further from the exemplary embodiment of Fig. 4 , the first input power source 102 and the second input power source 104 are configured to be grounded axially with respect to a stationary structure of the gas turbine engine 10 at a location in front of the combustion section 26 of the turbomachine 16. Pi? Specifically, for the embodiment shown, the gas turbine engine 10 includes the inter-shaft bearing 146 and a first thrust bearing 148 located forward of the combustion section 26 of the turbomachine 16 supporting the first input power source 102 and a second thrust bearing 150 also located forward of the combustion section 26 of the turbomachine 16 and supporting the second input power source 104.

Pi? specifically, for the embodiment shown, the inter-shaft bearing 146 ? the primary thrust bearing for the first input power source 102. Thrust loads from the inter-shaft bearing 146, however, are grounded axially with respect to a stationary structure of the gas turbine engine 10 by the first thrust bearing 148. The first thrust bearing 148 ? configured as a journal bearing positioned between the planetary gearbox 114 and the fan shaft 108 of the power output component 106. Thus, the first thrust bearing 148 can be configured as a journal bearing. be grounded axially to the power output component 106 and to the first input power source 102 at or near the gear set 100? of the gear set 100 (for example, with respect to the combustion section 26).

Briefly, it will appreciate? also that the bearing ? positioned at least partially in front of the second epicyclic gear 112 and at least partially behind the shaft extension 140. This? can? facilitate a group of gears axially more? compact 100 for the gas turbine engine 10. This configuration ? allowed at least in part by the conical configuration of the shaft extension 140, which defines the angle 142 with the axial centerline 12.

Will you appreciate it? that for the embodiment of Fig. 4 , at least part of the axial load on the power output component 106 is transferred to an engine frame 10 through the first thrust bearing 148 and the second thrust bearing 150. For example, at least a portion of the second portion of the axial load on the power output component 106 which is transferred through the group of gears 100 and more? specifically through the second epicyclic gear 112 to the second input power source 104, can? be transferred to an engine structure 10 through the second thrust bearing 150. This force can? provide propulsion thrust load for the gas turbine engine 10.

Of note, for the embodiment shown, the gas turbine engine 10 further includes a non-thrust bearing 149 which provides radial support for the power output component 106 at a separate location from the first thrust bearing. 148. The location of the undistinguished bearing 149 ? only by way of example and in other embodiments pu? be placed at any other suitable location.

Also, for the embodiment shown, the second thrust bearing 150 is similarly located at or near the of the gear set 100 (with respect to, for example, the combustion section 26). The second thrust bearing 150 also extends to the structural member 120 of the gas turbine engine 10 through the bearing support arm 151. The second thrust bearing 150 is the primary thrust bearing for the second input power source 104. Thus, the second thrust bearing 150 can? support all or substantially all thrust loads on the second input power source 104. However, a separate bearing (or non-thrust bearing) can? be provided at a location not shown (e.g., behind the combustion section 26) separately providing radial support for the second input power source 104.

Aspect to highlight, by axially grounding both the first input power source 102 and the second input power source 104 at or near the? of the gear group 100, in front of the combustion section 26 of the turbomachine 16, a quantity? of thermal expansion to which ? subjected the first input power source 102 over a length of the first power source between the first thrust bearing 148 and, for example, a first plurality of of turbine rotor blades 44 revolving with the first input power source 102, sar? substantially adapted to a quantity? of thermal expansion to which ? subject second input power source 104 along a length of second input power source 104 between second thrust bearing 150 and, for example, a second plurality of of turbine rotor blades 46 rotatable with the second input power source 104. Thus, the thrust bearings 146, 148, 150 can ensure that axial clearances are maintained within the turbine section 33, particularly when the turbine section 33 includes a counter-rotating turbine assembly (see, for example, FIG. 3 ). Also, placing the thrust bearings 146, 148, 150 in front of the combustion section 26 can? determine a less harsh environment for thrust bearings 146, 148, 150.

It will be appreciated, however, that the exemplary gas turbine engine 10 described above with reference to FIG. provided as an example only. In other exemplary embodiments, the gas turbine engine 10 may have any other suitable configuration. For example, an alternate exemplary embodiment ? shown in Fig. 9 . Fig. 9 provides a cross-sectional view of a gas turbine engine 10 according to another exemplary embodiment of the present disclosure. The exemplary gas turbine engine 10 of FIG. 9 can be configured in substantially the same manner as the exemplary gas turbine engine 10 of FIG. 4. For example, the exemplary gas turbine engine 10 of FIG. generally include a fan assembly 14 and a turbomachine 16, the turbomachine 16 including a first input power source 102, a second input power source 104, a power output component 106 and a gear set 100. The of gears 100 pu? likewise include a first epicyclic gear 110 and a second epicyclic gear 112, which define a first torque path from the first input power source 102 through the first epicyclic gear 110 to the power output component 106 and a second torque path from second input power source 104 through the second epicyclic gear 112 to the power output component 106.

Further, for the exemplary embodiment shown, the gas turbine engine 10 includes a plurality of of bearings that support the rotation of these various components. In particular, the exemplary gas turbine engine 10 of Fig. 9 generally includes an inter-shaft bearing 146 positioned between the first input power source 102 and the power output component 106, a first bearing 148 which supports an epicyclic gearbox 114 (on which the first planetary gear 110 and the second planetary gear 112 are rotatably mounted) and a second bearing 156 which supports rotation of the second input power source 104. Also, for the exemplary embodiment shown, one or more of these bearings 146, 152, 156 are configured as non-thrust bearings. Pi? specifically, for the embodiment shown, the inter-shaft bearing 146 and the second bearing 156 are instead configured as radial support bearings providing no or minimal axial support. For example, these bearings 146, 156 can be configured as roller bearings.

Will you appreciate it? that with such a configuration, the gas turbine engine 10 pu? include a first thrust bearing which supports rotation of the first input power source 102 at a location behind the combustion section 26 and a second thrust bearing which supports rotation of the second input power source 104 also at a location behind the combustion section 26. For example, the first and second thrust bearings may be positioned similarly to the bearings 40, 42 in FIG. 3.

In this way, it will be appreciated that an axial load on the fan assembly 14 and the power output component 106 may not be transferred from the power output component 106 to the first input power source 102 through the inter-shaft bearing 146 and the first bearing 148 (a journal bearing). However, the exemplary gear set 100 can? yet be configured to transfer an axial load from fan assembly 14 and power output component 106 to first input power source 102, second input power source 104, or both via gear set 100. specifically, as with the embodiment described above with respect to Fig. 4 , the first epicyclic gear 110, a first sun gear 128 of the first input power source 102 and an output crown gear 138 of the power output component 106 can be configured as a helical gear, such as a single helical gear. In this way, the gear group 100 can? defining a first axial load path from the power output component 106 to the first input power source 102 through the first epicyclic gear 110. Similarly, the second epicyclic gear 112, a second ring gear 138 of the second input power source 104 and a ring gear 138 of the power output component 106 can also each be configured as a helical gear, such as a single helical gear. In this way, the gear group 100 can? further define a second axial load path from the power output component 106 to the second input power source 104 through the second epicyclic gear 112.

Will you appreciate it? further that in still other exemplary embodiments, a gas turbine engine 10 according to an exemplary aspect of the present disclosure can yet to be configured in other ways. For example, another alternate exemplary embodiment of the present disclosure? shown in Fig. 10 . Fig. 10 provides a cross-sectional view of a gas turbine engine 10 according to another exemplary embodiment of the present disclosure. The exemplary gas turbine engine 10 of FIG. 10 can be configured in substantially the same manner as the exemplary gas turbine engine 10 of FIG. 4.

For example, the exemplary gas turbine engine 10 of FIG. 10 can generally include a fan assembly 14 and a turbomachine 16, the turbomachine 16 including a first input power source 102, a second input power source 104, a power output component 106 and a gear set 100. The of gears 100 pu? likewise include the first epicyclic gear 110 and the second epicyclic gear 112, defining a first torque path from the first input power source 102 through the first epicyclic gear 110 to the power output component 106 and a second torque path from the second input power source 104 through the second epicyclic gear 112 to the power output component 106.

Further, for the exemplary embodiment shown, the gas turbine engine 10 includes a plurality of of bearings that support the rotation of these various components. In particular, the exemplary gas turbine engine 10 of Fig. 10 generally includes an inter-shaft bearing 146 positioned between the first input power source 102 and the power output component 106 and a second thrust bearing 150 which supports the rotation of the second input power source 104. Furthermore, for the embodiment of Fig. 10 , the gas turbine engine 10 further includes a first thrust bearing 148 which supports the power output component 106. As with the form 4 embodiment, the inter-shaft bearings 146 in the second thrust bearing 150 are each configured as a thrust bearing to support the axial loads on those components and similarly, the first thrust bearing 148 ? configured as a thrust bearing. In this way, it will be appreciated that an axial load on the fan assembly 14 and on the power output component 106 can be transferred from the power output component 106 through the inter-shaft bearing 146 and to the first input power source 102. that both the first input power source 102 and the second input power source 104 are grounded along the axial direction at a location forward of the combustion section 26 of the turbomachine 16 and further? specifically in the vicinity? of the gear group 100. As discussed above, there? can? allow the desired maintenance of axial clearance, for example, in a counter-rotating turbine, while also allowing the bearings to be mounted in a less harsh environment.

However, for the exemplary embodiment shown, the turbomachine 16 is not configured to permit an axial load path through the first epicyclic gear 110, the second epicyclic gear 112, or both. Pi? Specifically, as noted above, the gear set 100 defines a first torque path that extends from the power output component 106 through the first epicyclic gear 110 to the first input power source 102. The gear set 100 defines also a second torque path extending from the power output component 106, through the second planetary gear 112, to the second input power source 104. For the embodiment shown, the gear set 100 includes at least one gear spur gear in the first torque path, includes at least one spur gear in the second torque path or both. Pi? Specifically, for the embodiment shown, the gear set 100 includes only spur gears which transfer torque in the first torque path and only spur gears which transfer torque in the second torque path. Thus, the gear group 100 is not? configured to provide a transfer of axial loads through the first torque path or through the second torque path.

Will you appreciate it? that as used herein, the term "spur gear" refers to a type of spur gear in which one edge of each tooth is straight and aligned parallel to a gear centerline (i.e. axis of rotation). For example, referring briefly to FIG. 11, by reference ? A pair of exemplary spur gears is shown. Pi? Specifically, Figure 11 shows a first spur gear 220 and a second spur gear 222 configured to mesh with the first spur gear 220. The first spur gear 220 includes a first plurality of of teeth 224 circumferentially spaced and oriented in a first direction 226 with respect to a first center line 228 of the first spur gear 220. The second spur gear 222 includes a second plurality of of teeth 230 circumferentially spaced apart and oriented in a second direction 232 with respect to a second center line 234 of the second spur gear 222. The first direction 226 is aligned parallel to the first center line 228 and the second direction 232 ? aligned parallel to the second centerline 234. For example, referring now also briefly to FIG. 12 , which provides a plan view of one side of the first spur gear 220 and the first plurality of of teeth 224, will you appreciate? that the first direction 226 of the first plurality? of teeth 224 ? aligned parallel to the first centerline 228, such that an angle between the first direction 226 and the first centerline 228 is 0 degrees or a de minimus angle (e.g., less than about 5 degrees). The second spur gear 222 pu? define the same angle. Spur gears generally allow torque to be transmitted within the driving force in a direction parallel to their center lines.

Referring back to Figure 10, you will appreciate the that the power output component 106 further includes a ring gear 138 configured to mesh with the second epicyclic gear 112, a fan shaft 108, and a shaft extension 140 extending from the fan shaft 108 to the gear crown gear 138. In the embodiment shown, little or no axial load is transferred from fan shaft 108 to crown gear 138 via shaft extension 140. As such, it will be appreciated that that the exemplary shaft extension 140 shown defines an extension angle 142 with the axial centerline 12 greater than or equal to about 80 degrees and less than or equal to about 95 degrees. Such a configuration can? facilitate group of gears axially more? compact 100.

Noteworthy, however, in other embodiments, the gear set 100 of Figure 10 may include at least one helical gear (or all helical gears) in the first torque path or in the second torque path. When gearset 100 includes helical gears in the second torque path, however, shaft extension 140 may having to be modified to transfer anticipated axial loads.

Will you appreciate it? that the embodiments described herein above are by way of example only. In other exemplary embodiments, pu? any other suitable configuration be provided. For example, while at least some of the embodiments discussed utilize single helical gear/single gears and clearances, other exemplary aspects may utilize double helical gear/double helical gears or other suitable helical gears.

Does the written description use examples to describe this disclosure, including how? best and also to enable any person skilled in the art to practice the disclosure, including to manufacture and use any device or system and to execute any incorporated methods. The patentable scope of protection of the disclosure ? defined by the claims and pu? include other examples conceived by those skilled in the art. Such other examples are intended to fall within the scope of the claims if they include structural elements which do not differ from the literal language of the claims or if they include equivalent structural elements with insubstantial differences from the literal languages of the claims.

Additional aspects are provided by the subject matter of the following clauses:

a gas turbine engine comprising: a fan assembly comprising a plurality of of fan blades; and a turbomachine including a compressor section, a combustion section and a turbine section in serial flow order, the turbomachine comprising a first input power source; a second input power source configured to counter-rotate with respect to the first input power source; a power output component operatively connected to the fan assembly; and a gear set located in front of the combustion section of the turbomachine, the gear set configured to receive power from the first input power source and the second input power source and to supply power to the power output component, the set of gears including a helical gear.

The gas turbine engine of one or more? of these terms, wherein the gear set includes a first epicyclic gear configured to operatively connect the first input power source to the power output component.

The gas turbine engine of one or more? of these clauses, wherein the first planetary gear comprises the helical gear, wherein the power output component comprises an output sun gear, and wherein the helical gear ? configured to mesh with the output sun gear.

The gas turbine engine of one or more? of these clauses, in which the helical gear ? a front gear of the first epicyclic gear, wherein the first epicyclic gear further comprises a rear gear, wherein the first input power source comprises a first sun gear, wherein the rear gear of the first epicyclic gear is configured to mesh with the first sun gear of the first input power source and wherein the back gear of the first planetary gear and the first sun gear are each configured as a helical gear.

The gas turbine engine of one or more? of these clauses, wherein the gear set further comprises a second epicyclic gear, wherein the second epicyclic gear is configured to operatively connect the second input power source to the power output component.

The gas turbine engine of one or more? of these terms, wherein the second epicyclic gear comprises a front gear and a rear gear, wherein the second input power source comprises a second sun gear, wherein the power output component comprises a ring gear, wherein the front gear of the second epicyclic gear ? configured to mesh with the ring gear and in which the rear gear of the second epicyclic gear is ? configured to mesh with the second sun gear.

The gas turbine engine of one or more? of these clauses, wherein the front and rear gears of the second planetary gear, the crown gear and the second sun gear are each configured as a helical gear.

The gas turbine engine of one or more? of these terms, wherein the gas turbine engine defines an axial centerline, wherein the power output component comprises a fan shaft and a shaft extension, wherein the shaft extension extends between the impeller shaft and the ring gear, wherein the shaft extension defines an angle with the axial center line greater than or equal to about 15 degrees and less than or equal to about 90 degrees.

The gas turbine engine of one or more? of these terms, further comprising: a structural member, wherein the gear set further comprises a planetary carrier, wherein the first planetary gear and the second planetary gear are each mounted on the planetary carrier and wherein the planetary carrier ? mounted on the structural member.

The gas turbine engine of one or more? of these terms, further comprising: a journal bearing positioned between the planetary gearbox and the power output component, wherein the journal bearing ? a thrust bearing.

The gas turbine engine of one or more? of these clauses, wherein the power output component comprises a ring gear operatively connected to the second epicyclic gear, an impeller shaft and a shaft extension, wherein the shaft extension extends between the impeller shaft and the crown gear, and in which the journal bearing ? positioned at least partially in front of the second epicyclic gear and at least partially behind the shaft extension.

The gas turbine engine of one or more? of these clauses, in which the helical gear ? a single helical gear.

The gas turbine engine of one or more? of these clauses, wherein the turbine section comprises a counter-rotating turbine having a first plurality of turbine rotor blades configured to rotate in a first direction and a second plurality of turbine rotor blades configured to rotate in a second direction opposite to the first direction, wherein the first input power source is revolving with the first plurality? of turbine rotor blades and in which the second input power source ? revolving with the second plurality? of turbine rotor blades.

The gas turbine engine of one or more? of these clauses, in which the first source of input power ? a low-speed input power source? and in which the second input power source ? a high-speed input power source.

The gas turbine engine of one or more? of these provisions, further comprising: an inter-shaft bearing positioned between the first input power source and the power output component.

The gas turbine engine of one or more? of these clauses, in which the inter-shaft bearing ? a thrust bearing.

The gas turbine engine of one or more? of these clauses, in which the inter-shaft bearing ? configured as a thrust bearing such that a first portion of an axial load on the power output component is configured to pass through the inter-shaft bearing to the first input power source and a second portion of the axial load on the component The power output source is configured to pass through the gear set by means of the helical gear to the first input power source.

The gas turbine engine of one or more? of these clauses, in which a third portion of the axial load on the power output component ? transferred to a structural member through a journal bearing.

The gas turbine engine of one or more? of these clauses, in which a second thrust bearing ? located forward of the combustion section of the turbomachinery and supports the second input power source.

The gas turbine engine of one or more? of these clauses, in which the inter-shaft bearing ? a roller bearing.

The gas turbine engine of one or more? thereof, further comprising: a first thrust bearing located aft of the combustion section of the turbomachine and supporting the first input power source; and a second thrust bearing located behind the combustion section of the turbomachine and supporting the second input power source.

The gas turbine engine of one or more? of these terms, wherein the gear set includes a first epicyclic gear configured to operatively connect the first input power source to the power output component and a second epicyclic gear configured to operatively connect the second input power source to the component of power output, wherein the first epicyclic gear comprises a first front gear configured as the helical gear and a first rear gear and wherein the second epicyclic gear comprises a second front gear and a second rear gear, wherein the first gear rear, the second front gear and the second rear gear are each configured as a helical gear.

A gear set for a gas turbine engine, the gas turbine engine including a fan assembly and a turbomachine, the turbomachine including a combustion section, a first input power source, a second input power source configured to counter-rotate with respect to the first input power source and a power output component operatively connected to the impeller assembly, the gear assembly comprising: a plurality? of gears configured to be located forward of the combustion section of the turbomachine when installed in the turbomachine, the gearset configured to receive power from the first input power source and the second input power source and to supply power to the output component of power, the gear set comprising a helical gear.

A gas turbine engine comprising: a fan assembly comprising a plurality of of fan blades; and a turbomachine including a compressor section, a combustion section and a turbine section in serial flow order, the turbomachine comprising a first input power source; a second input power source configured to counter-rotate with respect to the first input power source; a power output component operatively connected to the fan assembly; a gear set located forward of the combustion section of the turbomachine, the gear set configured to receive power from the first input power source and the second input power source and to supply power to the power output component; and an inter-shaft bearing positioned between the first input power source and the power output component.

The gas turbine engine of one or more? of these clauses, in which the inter-shaft bearing ? configured as a thrust bearing.

The gas turbine engine of one or more? of these terms, wherein the gear set defines a torque path from the first input power source to the power output component and wherein the gear set comprises at least a single helical gear in the torque path.

The gas turbine engine of one or more? of these clauses, wherein a first portion of an axial load on the power output component ? configured to pass through the inter-shaft bearing to the first input power source and a second portion of the axial load on the power output component ? configured to pass through the gear set by means of the single helical gear to the first input power source.

The gas turbine engine of one or more? of these clauses, wherein the gear set includes a first epicyclic gear configured to operatively connect the first input power source to the power output component and to an epicyclic gear carrier, how much the first epicyclic gear ? coupled to the planetary carrier, and wherein the gas turbine engine further comprises: a journal bearing positioned between the planetary carrier and the power output component, wherein the journal bearing is? a thrust bearing.

The gas turbine engine of one or more? of these provisions, further comprising: a second thrust bearing located forward of the combustion section of the turbomachinery and supporting the second input power source.

The gas turbine engine of one or more? of these terms, wherein the gearset defines a torque path from the first input power source to the power output component and wherein the gearset comprises a plurality of of spur gears in the torque path.

The gas turbine engine of one or more? of these clauses, in which the inter-shaft bearing ? located inwardly along a radial direction of at least one gear of the gear set.

The gas turbine engine of one or more? of these clauses, in which the inter-shaft bearing ? a roller bearing.

The gas turbine engine of one or more? of these clauses, in which the group of gears includes a plurality? of straight-toothed gears.

The gas turbine engine of one or more? of these clauses, wherein the turbine section comprises a counter-rotating turbine having a first plurality of turbine rotor blades configured to rotate in a first direction and a second plurality of turbine rotor blades configured to rotate in a second direction, wherein the first input power source is coupled to the first plurality? of turbine rotor blades and in which the second input power source ? coupled to the second plurality? of turbine rotor blades.

The gas turbine engine of one or more? of these terms, wherein the gear set includes a first planetary gear and a second planetary gear, wherein the gas turbine engine defines an axial centerline, wherein the power output component comprises a fan shaft, a a shaft extension and a spur gear, wherein the shaft extension extends between the impeller shaft and the spur gear, wherein the shaft extension defines an angle with the axial center line greater than or equal to approximately 15 degrees and less than or equal to approximately 90 degrees.

The gas turbine engine of one or more? of these terms, wherein the gear set includes a first planetary gear and a second planetary gear, wherein the gas turbine engine defines an axial centerline, wherein the power output component comprises a fan shaft, a a shaft extension and a spur gear, wherein the shaft extension extends between the impeller shaft and the spur gear, wherein the shaft extension defines an angle with the axial center line greater than or equal to approximately 80 degrees and less than or equal to approximately 95 degrees.

The gas turbine engine of one or more? of these clauses, in which the inter-shaft bearing ? configured as a roller bearing, wherein the gear set defines a torque path from the first input power source to the power output component and wherein the gear set comprises at least a single helical gear in the torque path.

The gas turbine engine of one or more? thereof, further comprising: a first thrust bearing located aft of the combustion section of the turbomachine and supporting the first input power source; and a second thrust bearing rearward in front of the turbomachine combustion section and supporting the second input power source.

An assembly for a gas turbine engine, the gas turbine engine including a fan assembly and a turbomachine, the turbomachine including a combustion section, a first input power source, a second input power source configured to counter-rotate with respect to the first input power source and a power output component operatively connected to the fan assembly, the assembly comprising: a gear set comprising a plurality of of gears configured to be located forward of the combustion section of the turbomachine when installed in the turbomachine, the gearset configured to receive power from the first input power source and the second input power source and to supply power to the output component of power and an inter-shaft bearing positioned between the first input power source and the power output component.

The group of one or more of these clauses, in which the inter-shaft bearing ? configured as a thrust bearing.

The group of one or more of these terms, wherein the gear set defines a torque path from the first input power source to the power output component and wherein the gear set comprises at least a single helical gear in the torque path.

The group of one or more of these clauses, wherein a first portion of an axial load on the power output component ? configured to pass through the inter-shaft bearing to the first input power source and a second portion of the axial load on the power output component ? configured to pass through the gear set by means of a single helical gear to the first input power source.

A gas turbine engine comprising: a fan assembly comprising a plurality of of fan blades; and a turbomachine including a compressor section, a combustion section and a turbine section in serial flow order, the turbomachine comprising a first input power source; a second input power source configured to counter-rotate with respect to the first input power source; a power output component operatively connected to the fan assembly; a gear set located forward of the combustion section of the turbomachine, the gear set configured to receive power from the first input power source and the second input power source and to supply power to the power output component; a first thrust bearing located forward of the combustion section of the turbomachine and supporting the first input power source; and a second thrust bearing located forward of the combustion section of the turbomachine and supporting the second input power source.

The gas turbine engine of one or more? of these clauses, in which the first thrust bearing ? an inter-shaft bearing positioned between the first input power source and the power output component.

The gas turbine engine of one or more? of these clauses, in which the first source of input power ? a low-speed input power source? and in which the second input power source ? a high-speed input power source.

The gas turbine engine of one or more? of these clauses, wherein the turbine section comprises a counter-rotating turbine having a first plurality of turbine rotor blades configured to rotate in a first direction and a second plurality of turbine rotor blades configured to rotate in a second direction, wherein the first input power source is coupled to the first plurality? of turbine rotor blades and in which the second input power source ? coupled to the second plurality? of turbine rotor blades.

The gas turbine engine of one or more? of these terms, wherein the gear set defines a torque path from the first input power source to the power output component and wherein the gear set comprises at least a single helical gear in the torque path.

The gas turbine engine of one or more? of these clauses, in which the first thrust bearing ? an inter-shaft bearing, in which a first portion of an axial load on the power output component is ? configured to pass through an intershaft bearing to the first input power source and a second portion of the axial load on the power output component ? configured to pass through the gear set by means of the single helical gear to the first input power source.

The gas turbine engine of one or more? of these clauses, wherein the gear set includes a first epicyclic gear configured to operatively connect the first input power source to the power output component and to an epicyclic gear carrier, when the first epicyclic gear ? coupled to the planetary carrier and wherein the gas turbine engine further comprises: a journal bearing positioned between the planetary carrier and the power output component, wherein the journal bearing is ? a thrust bearing.

The gas turbine engine of one or more? of these terms, wherein the gear set defines a torque path from the first input power source to the power output component and wherein the gear set includes at least one spur gear in the torque path.

The gas turbine engine of one or more? of these clauses, in which the first thrust bearing ? an inter-shaft bearing, in which substantially all of an axial load on the power output component ? configured to pass through the intershaft bearing to the first input power source.

The gas turbine engine of one or more? of these terms, wherein the gear set defines a torque path from the second input power source to the power output component and wherein the gear set includes at least one spur gear in the torque path.

Claims (10)

1. Gas turbine engine including: a group of impeller comprising a plurality? of fan blades; And a turbomachinery including a compressor section, a combustion section and a turbine section in serial flow order, the turbomachinery comprising a first input power source; a second input power source configured to counter-rotate with respect to the first input power source; a power output component operatively connected to the fan assembly; And a gear set located forward of the combustion section of the turbomachine, the gear set configured to receive power from the first input power source and the second input power source and to supply power to the power output component, the gear set gears including a helical gear. The gas turbine engine according to claim 1, wherein the gear set includes a first epicyclic gear configured to operatively connect the first input power source to the power output component. 3. A gas turbine engine according to claim 2, wherein the first planetary gear comprises the helical gear, wherein the power output component comprises an output sun gear and wherein the helical gear is configured to mesh with the output sun gear. 4. A gas turbine engine according to claim 3 wherein the helical gear is a front gear of the first epicyclic gear, wherein the first epicyclic gear further comprises a rear gear, wherein the first input power source comprises a first sun gear, wherein the rear gear of the first epicyclic gear is configured to mesh with the first sun gear of the first input power source and wherein the back gear of the first planetary gear and the first sun gear are each configured as a helical gear. 5. A gas turbine engine according to claim 2, wherein the gear set further comprises a second epicyclic gear, wherein the second epicyclic gear is ? configured to operatively connect the second input power source to the power output component. The gas turbine engine according to claim 5, wherein the second planetary gear comprises a front gear and a rear gear, wherein the second input power source comprises a second sun gear, wherein the power output component comprises a ring gear, in which the front gear of the second epicyclic gear ? configured to mesh with the ring gear and in which the rear gear of the second epicyclic gear is ? configured to mesh with the second sun gear. The gas turbine engine according to claim 6, wherein the front and rear gears of the second planetary gear, the crown gear and the second sun gear are each configured as a helical gear. The gas turbine engine according to claim 6, wherein the gas turbine engine defines an axial centerline, wherein the power output component comprises a fan shaft and a shaft extension, wherein the shaft extension extends between the impeller shaft and the spur gear, where the shaft extension defines an angle with the axial centerline greater than or equal to approximately 15 degrees and less than or equal to approximately 90 degrees . The gas turbine engine according to claim 5, further comprising: a structural member, wherein the gear set further comprises a planetary carrier, wherein the first planetary gear and the second planetary gear are each mounted on the planetary carrier and in which the epicyclic train carrier ? mounted on the structural member. The gas turbine engine according to claim 9 further comprising: a journal bearing positioned between the planetary gearbox and the power output component, wherein the journal bearing is ? a thrust bearing.